We will develop, improve, and maintain a scientific resource of mutant-bearing stocks, partially inbred, and inbred strains of rabbits and provide them to research workers at the Jackson Laboratory and elsewhere. The mutant pathologies and genetic uniformity of these rabbits make them valuable for studying processes related to constitutional diseases, growth, and reproductive disorders in man. We will accomplish these objectives by inbreeding, by maintenance, by characterization, by collaborative studies, and by distribution to qualified investigators of: (1) rabbits with specific genes such as adrenal hyperplasia (ah), ataxia (ax), buphthalmia (bu), audiogenic seizures (ep), chondrodystrophy (cd), osteopetrosis (os), dwarf (Dw), achondroplasia (ac), spina bifida (sb), hypogondia (hg), renal cysts (rc), mandibular prognathism (mp), lymphosarcoma (ha) (formerly designated as 1s), hemolytic anemia (ha), retroesophageal-right subclavian artery (res), seven genes at three gamma-globulin loci, five morphological hair characters, etc.; (2) rabbits with abnormalities such as hemiuterus, macrostomas, and scoliosis; and (3) rabbit inbred strains including the B/J strain now in its 28th generation of continuous brother-by-sister mating. We will also collect, analyze, and disseminate data on the morphological, physiological, hematological, biochemical, and vital characteristics of these stocks. A Handbook on Genetically Standardized JAX Rabbits is available. We also maintain a current bibliography on all known rabbit mutants.